Recent developments in theater and wide-screen home-theater projection systems include the development of Digital Light Processing (xe2x80x9cDLPxe2x80x9d) projectors. Unlike the older Cathode Ray Tube (xe2x80x9cCRTxe2x80x9d) projectors, the DLP projectors do not include coated tubes, but instead generate images by beaming light from a lamp to a surface of a Digital Micromirror Device (xe2x80x9cDMDxe2x80x9d). The DMD is commonly housed in a light engine portion of the DLP projector. The DLP projectors are relatively compact in comparison with their CRT counterparts and can produce high quality images without grainy scan lines when images from a standard video source are enlarged to fill a large screen.
U.S. Pat. No. 6,310,726 B1 discloses an image-projecting device that includes a relay lens that is capable of being shifted in at least one direction that is perpendicular to the optical axis of the device.
Japanese Patent Publication 05-027324 also discloses a projection-type display device with a lens moving mechanism that moves a condensing lens and a projecting lens. The lens moving mechanism includes two screw shafts rotatably interconnected with a belt and pulleys. Torque is transmitted to one of the screw shafts by a bevel gear system.
One embodiment of the invention provides an image projector having a selectively shiftable projector lens assembly. Another embodiment of the invention provides an apparatus for selectively shifting a projector lens assembly. In one embodiment, the image projector may include a projector housing, a light engine supported by the projector housing, and a projector lens assembly supported by the projector housing. The projector lens assembly defines an optical axis and is oriented relative to the light engine for receiving and projecting light emitted by the light engine. In one embodiment, the lens shifting apparatus may include a first plate movably coupled to the projector housing and supporting the projector lens assembly. The first plate may be selectively movable along a first axis perpendicular to the optical axis. The first plate may be movably coupled to a second plate which is movably supported by the projector housing for selective travel about a second axis that is perpendicular to the optical axis and the first axis.